In case equipment fails, the measure most widely taken is methods dependent mainly on manual intervention. The user calls a support center and describes the phenomena of the failure. Then, the user remedies it by himself/herself or request to dispatch service personnel depending on the severity of it. Meanwhile, for communication devices, remote control systems have been established wherein devices are remotely maintained and controlled. In such a system, the status of devices is remotely monitored and the setting thereof is remotely changed.
For example, a system disclosed in the official gazette JP-A No. 115393/2000 has been proposed. In the system, recovery from failure and the mitigation of phenomena are effected by transmission from a control center. The control center transmits recovery data or programs according to error information notified by machines. Further, failures are prevented from occurring. This is done by predicting the occurrence of error based on error history information collected at the control center and transmitting a remedying program.
FIG. 19 illustrates the configuration of such a system. A control center 167 and access points (hereafter, referred to as “APs”) 164 to 166 located in various places are connected with each other through a communication network 1611. Machine A 161, machine B 162 and machine C 163 as controlled devices are connected with AP 164. The control center 167 is connected with the machines 161 to 163 as controlled devices through respective APs 164 to 166. The control center 167 sends operation table data and programs for the machines 161 to 163, stored in a database (DB) 168, to the machines 161 to 163 and thereby maintains and controls the machines. If necessary, further, information is received from a remedying body 1610 or service personnel is dispatched from a service center 169 to cope with failures.
If a control center and a controlled device belong to different networks (for example, the device belongs to a private network and the control center belongs to a global network), direct accessing from one to the other is infeasible. In this case, a relaying function of some kind is required. Description will be given taking as an example the IPv4 (Internet Protocol Version 4) system which is presently a mainstream network protocol. In this system, local networks (Local Area Networks: hereafter, referred to as “LANs”) are set up in homes and companies because of insufficiency of number of addresses. Here, to access a global network from LAN, an address translation technique, such as NAT (Network Address Translator) is used. The NAT translates private addresses contained in headers into global addresses but does not translate private addresses contained in data. Therefore, if a control center attempts to make an access using a private address contained in data, relaying operation cannot made by the NAT.
There are some methods for solving this problem. One of the methods is that a relaying device is placed between the control center and the controlled device and the relaying device is caused to manage controlled device addresses and a list of commands as tables. The control center sends a command to the relaying device. The relaying device interprets the received command and, referencing the command table, sends the command to the appropriate controlled device.
In this case, it is required to hold the command table at the relaying device. Therefore, if a new controlled device is added and commands are altered, the tables must be updated and this makes operation complicated.
Further, the relaying device must accept every command once and interpret it. Therefore, if a number of controlled devices or commands is increased, the amount of data in the command table becomes vast. This poses a problem of increase in the size of the relaying device.
The official gazette JP-A No. 115393/2000 states that the control center 167 or the machines 161 to 163 do not communicate directly with each other and other equipment may mediate between them for relay. However, the gazette does not refer to relaying methods and a problem associated with cases where control data contains a device address remains unsolved.
Even in an environment wherein remote control can be exercised from a control center, conventionally, only predetermined operation can be performed on predetermined devices. Further, operating procedures for remote control and data required for control vary from one manufacturer to another and from one device to another. This imposes an enormous burden both on operators who perform remote control and on controlled devices. On this account, it is difficult to systematically manage and control networks wherein devices of different manufacturers or different types coreside.
Further, it is required to keep information, required for controlling devices, at a control center. Therefore, each time an upgrade is provided or a device to be controlled is added, control information must be added or updated. This forces a large amount of labor to be expended in database management. Each error is different from another and measures against error may be different on an error-by-error basis. In this case, storing the know-how to remedy each of them poses a problem that immense maintenance cost is required.
Further, the official gazette JP-A No. 115393/2000 assumes that remedying programs against errors which may occur in devices can be identified to some extent. The gazette does not mention that the cause of an error is pinpointed through operation from a control center.
The present invention is intended, for example, to make it possible for an operator at an operation center remotely located to remotely control devices belonging to different networks with ease.